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Free keywords:
genetic variance; Red Queen; resource dynamics; spatial variation; tangled bank
Abstract:
Questions: How are the prevalence of sexual reproduction and the phenomenon of geographic
parthenogenesis related to resource availability? What is the pattern in space of resource and
consumer dynamics?
Mathematical methods: A population dynamics model with structured resources in short
supply, including a spatial gradient of consumer mortality and resource diversity. Species are
modelled using quantitative genetics, combined with random mating for sexuals and clonal
reproduction for asexuals.
Key assumptions: Resources are limited and re-grow slowly. Only a few consumer genotypes
can co-exist locally. The twofold cost of sex is incurred once per season.
Conclusions: The advantage of sexual reproduction is due to the ability of the sexual
population to generate offspring that can use resources that have not been exploited for some
time. Resource use of the sexual population, therefore, changes continuously. This advantage
is most significant at the centre of a species’ range.
